Problem: Simplify the following expression: $k = \dfrac{3z + 4y}{5z} - \dfrac{3x + y}{5z}$ You can assume $x,y,z \neq 0$.
Answer: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{3z + 4y - (3x + y)}{5z}$ $k = \dfrac{3z + 3y - 3x}{5z}$